Nanny McPhee, she does not belong to any agency. She is a government Nanny of such intellect and impeccable morals who works in magical and mysterious ways, her job is to confront conflict of naughty children and turn them into well behaved, good boys and girls. A job she takes great pleasure in carrying out.
The brown family, Mr Brown a widower (played by Colin Firth) is a single parent who has seven children. They are all very bright and very clever each and every one of them however on the downside they are incredibly mischief and very naughty. They have got rid of every Nanny in town and Mr Brown is left in a bit of a pickle not knowing what to do, then he comes across a new Nanny, a Nanny which is not on anyone's books. Nanny McPhee, who just turns up out of blue one evening and get straight to work on Mr Brown's children. Emma Thompson stars as a governess who uses magic to rein in the behaviour of seven ne'er-do-well children in her charge.
The story is very well done, it's well written and well acted and therefore clearly communicated as being this live action fairy tale like story which isn't nasty or bad. It's a little sad that the mother has passed away and that the children are left absent of a motherly figure, but there isn't anything majorly upsetting or disconcerting about this story at all.
I think it's adaptation of the Cinderella story, where the parent dies and the child gets a new step parent who is horrid to them. One of the characters Evangeline is reading a book and is learning how to read. She never finishes it, but the story she's reading in the book basically the life of the children in this story now. Mr Brown gets funding from his Great Aunt Adelaide who is rich and she sends him a letter which basically says that he has to re-marry or the allowance stops and if the allowance stops he can't afford to keep the children, the house goes and everything goes to pot. In hope of avoiding this, Mr Brown sets his eyes on marrying Mrs Quickly who is in every sense of the word a vile woman and is dreadful.
In a happily ever after scenario Mr Brown doesn't marry Mrs Quickly, instead he marries Evangeline. And of course when the children want Nanny McPhee but no longer need her, then she has to go. It's rather sad really, but there it is. But it's through her decline and her guidance the children learn to be better then before and that's the whole point behind it, amongst many other things.